linux-kernel - [PATCH 18/32] softirq: Introduce disabled softirq vectors bits

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Date:   Tue, 12 Feb 2019 18:14:09 +0100
From:   Frederic Weisbecker <frederic@...nel.org>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Frederic Weisbecker <frederic@...nel.org>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Mauro Carvalho Chehab <mchehab@...pensource.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        "David S . Miller" <davem@...emloft.net>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>,
        Frederic Weisbecker <fweisbec@...il.com>,
        Pavan Kondeti <pkondeti@...eaurora.org>,
        Ingo Molnar <mingo@...nel.org>,
        Joel Fernandes <joel@...lfernandes.org>
Subject: [PATCH 18/32] softirq: Introduce disabled softirq vectors bits

Disabling the softirqs is currently an all-or-nothing operation: either
all softirqs are enabled or none of them. However we plan to introduce a
per vector granularity of this ability to improve latency response and
make each softirq vector interruptible by the others.

The first step carried here is to provide the necessary APIs to control
the per-vector enable bits.

Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
Cc: Mauro Carvalho Chehab <mchehab@...pensource.com>
Cc: Joel Fernandes <joel@...lfernandes.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Pavan Kondeti <pkondeti@...eaurora.org>
Cc: Paul E . McKenney <paulmck@...ux.vnet.ibm.com>
Cc: David S . Miller <davem@...emloft.net>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
---
 arch/s390/include/asm/hardirq.h |  9 ++++--
 include/linux/interrupt.h       | 53 ++++++++++++++++++++++++++++++---
 2 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/arch/s390/include/asm/hardirq.h b/arch/s390/include/asm/hardirq.h
index 54e81f520175..377fd4184f86 100644
--- a/arch/s390/include/asm/hardirq.h
+++ b/arch/s390/include/asm/hardirq.h
@@ -13,9 +13,14 @@
 
 #include <asm/lowcore.h>
 
-#define local_softirq_pending() (S390_lowcore.softirq_data)
-#define softirq_pending_clear_mask(x) (S390_lowcore.softirq_data &= ~(x))
+#define local_softirq_data() (S390_lowcore.softirq_data)
+#define local_softirq_pending() (local_softirq_data() & SOFTIRQ_PENDING_MASK)
+#define local_softirq_disabled() (local_softirq_data() & ~SOFTIRQ_PENDING_MASK)
+#define softirq_enabled_set_mask(x) (S390_lowcore.softirq_data |= ((x) << SOFTIRQ_ENABLED_SHIFT))
+#define softirq_enabled_clear_mask(x) (S390_lowcore.softirq_data &= ~((x) << SOFTIRQ_ENABLED_SHIFT))
+#define softirq_enabled_set(x) (S390_lowcore.softirq_data = ((x) << SOFTIRQ_ENABLED_SHIFT))
 #define softirq_pending_set_mask(x)  (S390_lowcore.softirq_data |= (x))
+#define softirq_pending_clear_mask(x) (S390_lowcore.softirq_data &= ~(x))
 
 #define __ARCH_IRQ_STAT
 #define __ARCH_HAS_DO_SOFTIRQ
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index c402770ae45b..1a08fb0e4781 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -474,16 +474,61 @@ enum
 #define SOFTIRQ_STOP_IDLE_MASK (~(1 << RCU_SOFTIRQ))
 #define SOFTIRQ_ALL_MASK (BIT(NR_SOFTIRQS) - 1)
 
-#ifndef local_softirq_pending
+#define SOFTIRQ_ENABLED_SHIFT 16
+#define SOFTIRQ_PENDING_MASK (BIT(SOFTIRQ_ENABLED_SHIFT) - 1)
+
+
+#ifndef local_softirq_data
 
 #ifndef local_softirq_data_ref
 #define local_softirq_data_ref irq_stat.__softirq_data
 #endif
 
-#define local_softirq_pending()	(__this_cpu_read(local_softirq_data_ref))
-#define softirq_pending_clear_mask(x)	(__this_cpu_and(local_softirq_data_ref, ~(x)))
-#define softirq_pending_set_mask(x)	(__this_cpu_or(local_softirq_data_ref, (x)))
+static inline unsigned int local_softirq_data(void)
+{
+	return __this_cpu_read(local_softirq_data_ref);
+}
 
+static inline unsigned int local_softirq_enabled(void)
+{
+	return local_softirq_data() >> SOFTIRQ_ENABLED_SHIFT;
+}
+
+static inline unsigned int local_softirq_pending(void)
+{
+	return local_softirq_data() & SOFTIRQ_PENDING_MASK;
+}
+
+static inline void softirq_enabled_clear_mask(unsigned int enabled)
+{
+	enabled <<= SOFTIRQ_ENABLED_SHIFT;
+	__this_cpu_and(local_softirq_data_ref, ~enabled);
+}
+
+static inline void softirq_enabled_set_mask(unsigned int enabled)
+{
+	enabled <<= SOFTIRQ_ENABLED_SHIFT;
+	__this_cpu_or(local_softirq_data_ref, enabled);
+}
+
+static inline void softirq_enabled_set(unsigned int enabled)
+{
+	unsigned int data;
+
+	data = enabled << SOFTIRQ_ENABLED_SHIFT;
+	data |= local_softirq_pending();
+	__this_cpu_write(local_softirq_data_ref, data);
+}
+
+static inline void softirq_pending_clear_mask(unsigned int pending)
+{
+	__this_cpu_and(local_softirq_data_ref, ~pending);
+}
+
+static inline void softirq_pending_set_mask(unsigned int pending)
+{
+	__this_cpu_or(local_softirq_data_ref, pending);
+}
 #endif /* local_softirq_pending */
 
 /* map softirq index to softirq name. update 'softirq_to_name' in
-- 
2.17.1